CARACAS, Feb 24 (Reuters) - Anti-government demonstrators set up barricades in Venezuela's capital on Monday, snarling traffic, despite calls from within the opposition to rein in protests in which at least 11 people have died in the OPEC nation.

Traffic slowed to a crawl around Caracas, and many people stayed at home, as protesters burned trash and piled debris along main avenues a day after opposition leader Henrique Capriles called on them to keep demonstrations peaceful.

The most sustained unrest in Venezuela for a decade is the biggest challenge to President Nicolas Maduro's 10-month-old government, though there is not sign it will topple him nor affect oil shipments from Latin America's biggest exporter.

Capriles, 41, was invited to meet Maduro in the afternoon as part of a gathering of mayors and governors that could open up communications between the two sides but may not be able to stem the nearly two weeks of street violence.

"If there's one thing these violent protests have done, it's unite 'Chavismo'," Maduro said on Sunday night, using the term for government supporters coined during the 14-year rule of his predecessor, Hugo Chavez.

Capriles and other opposition figureheads are demanding that the government release imprisoned protest leader Leopoldo Lopez and about a dozen jailed student demonstrators.

They also want Maduro to disarm pro-government gangs and address national issues ranging from crime to shortages of basic products. Hardline student protesters, though, are demanding that Maduro step down, less than a year into his term.

The president, a 51-year-old former union activist who has made preserving Chavez's legacy the centerpiece of his rule, accuses opponents of planning a coup backed by Washington.

'NICOLAS: YOU ARE A ... MISTAKE'

Capriles, who has seen his leadership of the opposition upstaged by Lopez's street activism, lashed Maduro for talking "rubbish" and said he was unsure if he would attend the meeting scheduled for the afternoon at the presidential palace.

"After so many lies and insults, we are consulting communities about our attendance," he said via Twitter.

"Nicolas, you are a grave mistake in Venezuela's history."

Both sides were planning meetings and rallies on Monday, with Lopez's wife due to address media in a public square, and the government organizing a rally of motorcyclists.

Relatives of Lopez, a 42-year-old Harvard-educated economist and firebrand opposition leader, said he was bearing up at Ramo Verde prison outside Caracas.

"He's fine. He's strong. But he's a prisoner and for a mother, it's devastating to have a son in jail," his mother Antonieta Mendoza de Lopez told Reuters.

The protests that Lopez spearheaded from the start of February were initially seen as a renewal of a stagnant opposition movement, but have risked alienating moderates.

Roadblocks of burning trash and clashes between rock-throwing students and tear-gas-lobbing troops have shown no sign of forcing Maduro from power but have become an annoyance for the mostly well-to-do neighborhoods where they take place.

"This is brutality. We are fighting for our freedom because when we go to the supermarket there's no flour, there's no sugar," said Yesenia Alvarado, 29, an architect, at the upscale Plaza Altamira where a barricade was blocking traffic.

"We have to paralyze the city."

As she spoke, a man driving a pickup attempted to force his way through the barricade, at one point getting out and piling debris into the back of the truck. Angry demonstrators restored the barricade and prevented him from moving ahead.

Residents of Caracas' poorer west side have staged only a few minor demonstrations, though government critics there have joined traditional protests of banging pots and pans at their windows during Maduro's hours-long television broadcasts.

The wave of violence has shifted attention away from economic troubles including inflation of 56 percent, slowing growth, and shortages of staple goods such as milk and flour.

The opposition blames these problems on Chavez's economic legacy of nationalizations, currency controls and constant confrontation with businesses.

They say socialism has crippled private enterprise and weakened state institutions while spawning a nepotistic elite that enriches itself with the country's oil wealth.

Maduro calls it an "economic war" led by the opposition. The former bus driver calls himself the "son" of Chavez and has vowed to continue the generous public spending that helped reduce poverty and propelled the late president to repeated election victories over 14 years. (Reporting by Brian Ellsworth; Editing by James Dalgleish)